SERVICE (Cont) - TM-5-4120-393-140232

TM 5-4120-393-14

5-12. Leak Testing Refrigerant System (cont)

(3) Connect a drum of refrigerant-22 to the center hose connection of the charging manifold.

CAUTION

Connect the refrigerant-22 drum so that only gas will be used for pressurization.

(4) Open both unit service valves and the charging manifold valves.

(5) Open the refrigerant drum valve slightly and adjust as necessary to prevent formation of frost, and allow

system pressure to build up until the gages read 40-50 psi (2.8-3.5 kg/cm ).

(6) Close the charging manifold valves and the refrigerant drum valve.

(7) Remove the refrigerant-22 drum from the center hose connection.

(8) Connect a nitrogen regulator and cylinder of dry nitrogen to the center hose connection.

(9) Open the charging manifold valves and the nitrogen cylinder and regulator valve. Allow system pressure to

build up until gages read 350 psi (24.7 kg/cm ).

(10)Perform leak tests, then discharge and purge the system, in accordance with paragraphs 5-9 and 5-10 before

performing maintenance, or before evacuating and charging the system, as appropriate.

Always perform a final leak test after performing any repair or replacement of components before the air conditioner is

reassembled and the refrigeration system is evacuated and charged.

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